U.S. Pat. Pub. No. US 2012/0164753, titled “MONOLITHIC FBAR-CMOS STRUCTURE SUCH AS FOR MASS SENSING,” published on Jun. 28, 2012, is directed toward an apparatus that comprises a thin-film bulk acoustic resonator such as can include an acoustic mirror, a piezoelectric region acoustically coupled to the acoustic mirror, and first and second conductors that can be electrically coupled to the piezoelectric region, and applications thereof.